Knife steel



March 7, 1950 s N 2,499,786

KNIFE STEEL Filed Aug. 2, 1948 JNVENTOR YRMH SHAW A T TOR/VEX PatentedMar. 7, 1950 UNITED STATES tPATENT glam OFFICE 10 Claims.

The present invention relates to knife steels. While the invention is ofgeneral applicability and is suitable for home use, it is particularlyuseful in butcher shops and other establishments where the use of verysharp knives is essential to the trade.

Knife steels comprising a rod of steel, usually tapered and roughened,have long been used for increasing the cutting properties of knives. Theaction of the steel on the knife is apparently more of a stroppingaction tending to line up the microscopic sections of the cutting edgerather than an abrasive action intended to remove material from theknife.

In a butcher shop, a knife steel is usually hung over, or provided near,every chopping block or cutting table. Each time, before cutting a pieceof meat, the butcher customarily reaches for the steel, strokes theknife on it several times, stroking first one side and then the other,and after he has finished he puts the steel back in the place where itis kept. This requires time and effort which, when magnified byrecurring dozens or perhaps hundreds of times a day, reachesconsiderable proportions. It means loss of time and increase of fatigue.

Moreover, considerable skill is required in steeling a knife properlywith the conventional steel. The stroking of the knife and the angle ofcontact between the knife and the steel must both be just right. This isno problem to an expert butcher. However, in these days of scarcity ofskilled craftsmen, it is frequently necessary to employ persons who arenot experts. Moreover, conventional knife steels have never been any toosatisfactory for home use since most householders are not sufficientlyskillful in using them.

It is an object of the present invention to provide a knife steel whichcan be mounted on the side of a chopping block or cutting table, or inother convenient location, and is used merely by drawing a knife throughit without removing the steel from its support. The time and effortrequired in reaching for a steel and then putting it back in place iswholly eliminated since the steel in accordance with the presentinvention is always ready for use and need not be moved. Still more timeis saved by the fact that the knife need be drawn through the deviceonly one or two times to produce a fine edge. A further advantage isthat use of my novel knife steel requires little or no skill to produceexcellent results. It is, hence, ideally suitable for home use as wellas for use in butcher shops, packing plants,

hotels, restaurants and other commercial establishments.

Other objects and advantages of my invention will appear from thefollowing description of the preferred embodiment of the invention whichhas been illustrated by way of example in the accompanying drawings.

In the drawings:

Fig. l is a side elevation of a knife-steel in accordance with thepresent invention.

Fig. 2 is a top view.

Fig. 3 is an end view as seen from the left hand end of Fig. 1.

Fig. 4 is a fragmentary cross-section of one of the spring bracketstaken approximately on the line 4-4 of Fig. 1.

Fig. 5 is a View similar to Fig. 2, but showing a modification.

Fig. 6 is a cross-section approximately on the line 6-6 of Fig. 5.

Fig. '7 is a diagrammatic view representing the outline of across-section taken approximately on the line 'l-l in Fig. 1 but on anenlarged scale and showing only the outlines of the cross-section.

The embodiment of my invention shown in Figs. 1 to i comprises a base, apair of reversibly symmerical elongated knife steel sections havinginner surfaces which are substantially in contact for a portion of theirlength and gradually diverge at one end in a sharp V and resilient meansfor pivotally mounting the steel sections on the base so as to turnabout their longitudinal axes and to be resiliently pressed into contactwith one another while being separable against the action of the springbrackets to allow a knife to be drawn between the sections. n

The frame or base It] can be of any suitable form and material, beingshown as a flat plate having a plurality of screw holes H for attachingit to the side of a chopping block or cutting table so that the baseplate is substantially vertical. These screw holes are shown merely byway of example, it being understood that any other suitable attachingmeans can be provided.

The steel sections I2 and 13 are similar to sections of a conventionalknife steel. In other words, each of the steel sections comprises alength of hardened steel rod which is preferably magnetized andpreferably has its surface slightly rilled or roughened, for example byfine longitudinally extending ribs and grooves. The steels are shown asbeing of ovoid cross-section (Fig. '7), the term ovoid being usedgenerically to designate a figure having a major axis and a minor axis,such for example, as an ellipse or semi-ellipse or a crescent or doublecrescent or slope gradually inwardly and meet the base such as thatillustrated in Fig. '7.

The steels l2 and I3 are of such shape and are mounted in such relationto one another that their inner or meeting faces are in contact, orsubstantially in contact, with one another throughout a portion of theirlength and then gradually diverge in the form of a sharp V (Figs. 2 and3). The steel sections may be substantially straight, in which event theportions of the surface that are in contact are progressively flatteneda greater amount in order to provide substantial contact over anappreciable increment of length. Alternatively, at least one of thesections is curved in a longitudinal direction in order to provide thedesired contact and divergence. In the preferred form of the inventionshown in Figs. 1 to 4, both steel sections are curved, being reverselysymmetrical to one another. As will be seen in Figs. 2 and 3, the lowerportions of the steels are approximately straight to provide substantialcontact between the two steels for a distance preferably amounting to atleast one-quarter, and not more than three quarters, the length of thesteel section. The upper end portions of the steel sections are curvedoutwardly from one another so. as to diverge in a sharp V.

At opposite ends, the steel sections i2 and I3 are provided with meansfor mounting the sections on the base l0. At least one, and preferablyboth, of the sections are pivotally mounted so as to be capable ofturning a limited amount about their respective longitudinal axes. Inthe form shown in the drawings, the steel section [2 ends with axiallyprojecting shaft portions i5 and IS. The steel section 13 is in likemanner provided with axially projecting shaft portions l1 and I8. Theseprojecting shaft portions may be integral with the steel sections or maybe in the form of stub shafts or pins set into holes in the end of thesteel section. It will be understood that alternative pivotal mountingmeans can be provided, as for example, merely by drilling holes in theends of the steel sections to receive pins or other projections mountedOn the base.

The steel sections are mounted on the base in such position that, exceptfor their divergence, they are approximately parallel to the base butare at an appreciable angle to the horizontal, for example an angle ofnot less than degrees and preferably 20 degrees or more. Thelongitudinal axes of the two sections i2 and I3 are in a common planewhich is approximately perpendicular to the plane of the base. In theembodiment shown in Figs. 1 to 4, the steel section 12 is supported bybrackets 2| and 22 comprising strips of spring steel secured to the baseby any suitable means, such as screws or rivets 23 and engaging the stubshafts l5 and 18 respectively in such manner as to permit pivotalmovement of the steel section l2 about its longitudinal aXis. Pivotalconnection is conveniently provided merely by curling the ends of thebracket strips 2! and 22 around the shaft portions !5 and 56respectively.

The other steel section I3 is mounted on the base by somewhat similarspring brackets 25 and 2B which are, however, considerably longer andare secured to the base at a considerable distance below the steels bysuitable screws, rivets, or other fastening means, 21. The upperportions of the brackets 25 and 26 are approximately parallel with thebase. The lower portions curve in a sharp angle, as indicated at 23. Thespring strips forming the brackets 25 and 26 are preferably convex ontheir inner surfaces, as illustrated in Fig. 4. In addition to theadvantages pointed out below, this form of strip permits the use oflighter strip while still securing the required stiffness. Instead ofusing strip stock for the spring brackets, round wire or other stock maybe used. For example, the brackets can be formed of relatively heavyspring wire having the end portions bent at approximately right anglesand projecting into holes in the ends of the steel sections i2 and [3 toprovide the desired pivotal mounting.

The spring brackets, and in particular the longer spring brackets 25 and26, resiliently press the steel sections l2 and I3 into contact with oneanother. The bracket 26, by virtue of being longer and hence somewhatmore flexible, provides lighter spring pressure than the bracket 25.

The knife steel in accordance with my invention is used simply bydrawing the edge of the knife blade through the sharp V between thesteel sections I2 and 13. The position in which the steel sections aremounted makes it easy and natural for the blade to be drawn through inproper relation to the steels. As the blade is drawn through with aslight amount of downward pressure, it passes down between the steelsections, separating them slightly against the resilient action of thespring brackets. The resiliency of the brackets assures the properpressure between the steels and the knife blade throughout the draw. Theshape of the brackets and their relative stiffness are such that correctpressure and correct angle of contact are assured at all times.

As the knife blade is drawn between the steel sections, the sectionstend to turn on their longitudinal axes, such turning being permitted bythe pivotal mounting of the sections. This movement of the steels hastwo effects. It presents new surfaces of the steels to the knife bladeand, in cooperation with the spring supports, it assures firm contactbetween the steels and the knife. As illustrated in Fig. 7 whichrepresents diagrammatically the cross-sectional outline of the steelsand their respective pivotal axes, the curvature of the inner or workingface of each steel is less than that of a circle having a radius equalto the distance from the pivotal axis 0 of the section to the nearestpoint C of the working face ACB. In other words the curvature of thesurface ACB is less, i. e., flatter than that of a circle having aradius equal to the distance ll-C. The distance from the pivotal center0 to the edges A and B of the working face is greater than the distancefrom 0 to the midpoint C. Normally, the midpoints C of the oppositeworking faces of the two steels are in contact with one another. As thesections turn slightly about their pivotal axes 0 due to the friction ofthe knife blade as it is drawn through between them, the pivotalmovement tends to bring into contact with the blade new surfaces of thesteel, for example siu'faces D, which are more distant from the pivotalaxes than the surfaces C. This causes the steels to press firmly on theknife blade so that predetermined pressure of contact is assured.

It is intended for the knife blade to be drawn between the steels in adirection approximately parallel to its cutting edge. If, through theapplication of excessive downward pressure, the

knife is forced all the way down so as to come out below the steels, nodamage is done since the way in which the spring brackets 25 and 26 aremounted provides adequate clearance. Moreover, even if the blade shouldstrike one of the brackets, it would be a glancing blow on a convexsurface similar to that of the steels so that the edge will not beappreciably blunted. The same is true even if the knife edge should comeall the way down to the point at which the bracket is attached to thebase, since the sharp V 28 between the bracket and the base (Fig. 3) issimilar to the V between the steel sections and, hence, exercises asharpening rather than a dulling action.

The embodiment of my invention shown in Figs. 5 and 6 is basically thesame as that of Figs. 1 to 4 and like parts are designated by the samereference numerals. The embodiment of Figs. 5 and 6 is different in thatportions of the steel sections H2 and H3 are cut away to accommodateinserts 32 and 33 of an abrasive material, for example, Carborundum. Theabrasive inserts 32 and 33 are held in place by suitable means, forexample, by providing dovetailing surfaces. Alternatively, they may beheld by spring clips 35, as illustrated in Figs. 5 and 6. The workingsurfaces of the abrasive inserts form smooth continuations of theworking surfaces of the respective steels. However, as the abrasivematerial will usually wear more rapidly than the steel, the leading edgeof the steel section may be rounded slightly so that the knife bladedoes not strike any sharp corner. The abrasive inserts are replaceableso that they may be renewed from time to time, as desired, or may bereplaced by inserts of finer or coarser abrasive, as desired.

The working surfaces of the sections H2 and H3 are thus formed ofabrasive material for a portion of their length and of steel in anotherportion of their length. The portion of knife steel and portion ofabrasive may be united in other ways, for example, by mounting both ofthem end to end on a suitable backing strip. In using the embodiment ofFigs. 5 and 6, the knife is first drawn through between the abrasiveportions 32 and 333 and then drawn through between the steel portions H2and H3. While the steel portions H2 and H3 are shown in Fig 5 as beingsubstantially parallel and in contact, it will be appreciated that,because of the greater resiliency of the bracket 25, the steels will beslightly separated and form a sharp V with one another as the knifeblade is drawn down between them. The embodiments of Figs. 5 and 6 thusprovides both an effective abrasive action and an effective steelingaction.

While the invention has been described with reference to the specificembodiment illustrated in the drawings, it will be understood that theseare shown merely by way of example and that modifications may be made inthem within the scope of the appendant claims. The invention thusprovides a knife steel which is so convenient to use as to make possiblesubstantial savings in time and effort in establishments such as butchershops, meat-packing plants, hotels and restaurants, and is substantiallyfoolproof so that it can be used even by an inexperienced person and is,hence, eminently suitable for household use as well as commercially.

I claim:

1. A knife steel comprising a pair of reversely symmetrical elongatedknife steel sections having inner surfaces which are substantiallyparallel for a portion of their length and gradually diverge at at leastone end, means for pivotally mounting each of the sections to turn aboutits longitudinal axis, the mounting means of at least one of the steelsections being resilient to press the parallel surface portions of thesections resiliently into contact with one another, the inner surfacesof said parallel portions being of less curvature in cross section thana circle having a radius equal to the distance from the respectivepivotal axes of said sections to the central portions of said surfaces.

2. A knife steel comprising a pair of reversely symmetrical knife steelsections of non-circular cross section, means for pivotally mountingsaid sections to form a sharp V with one another and to turn about theirrespective longitudinal axes, said axes being located in a common plane,the mounting means of at least one of the sections being resilient topress said sections resiliently together so that they are normally incontact but are separable to allow a knife to be drawn between them.

3. A knife steel comprising a vertical base plate, a pair of elongatedknife steel sections at least one of which is curved longitudinally,means for pivotally mounting said sections to form a sharp V with oneanother and to turn about their respective longitudinal axes, said axesbeing normally disposed in a common plane, the mounting means of atleast one of the sections being resilient to press said sectionsnormally into contact with one another but to permit their separationagainst the action of said resilient mounting to allow a knife to bedrawn between the sections.

4. A knife steel comprising a vertical base, an elongated steel sectionmounted on the base substantially parallel thereto and at an angle tothe horizontal, a second similar steel section, spring brackets attachedto the base a substantial distance below the first steel section andpivotally supporting the second section by its opposite ends so as toform a sharp V with the first section with the axes of the two sectionsin a common plane perpendicular to the base, the second section beingresiliently pressed against the first section by the spring bracketswhile permitting sufficient separation of the sections against theaction of the spring brackets to allow a knife to be drawn between thesections.

5. A knife steel according to claim 4, in which the upper and innersides of said spring brackets are convex.

6. A knife steel comprising a vertical base, a pair of elongated,longitudinally curved knife steel sections of ovoid cross section, apair of spaced brackets secured to the base and pivotally supporting oneof said sections by its opposite ends in a position approximatelyparallel to the base and at an angle to the horizontal, a second pair ofspring brackets attached to the base a substantial distance below thefirst section and pivotally supporting the second section by itsopposite ends so as to form a sharp V with the first section with thelongitudinal axes of the two sections in a common plane perpendicular tothe base, the second section being resiliently pressed against the firstsection by said spring brackets.

'7. A knife steel according to claim 6, in which each steel is providedfor in the upper portion of its length with an insert of abrasivematerial.

8. A knife steel comprising a pair of elongated sections, means forpivotally mounting said sections to forma sharp V with one another andto turn about their respective longitudinal axes, the mounting means ofat least one of the sections being resilient to press said sectionsresiliently into contact with one another while permitting theirseparation against the action of the resilient mounting to allow a knifeblade to be drawn between them, the knife engaging portion of oneportion of each section comprising a section of knife steel and theknife engaging portion of another portion comprising an abrasivesection.

9. In a knife sharpener, a composite sharpening clement comprising asection of knife steel, said section of steel being reduced in crosssection for a portion of its length to provide a supporting face setback from the working face of the adjacent full cross section portion ofthe steel, an abrasive stone supported on said supporting face anddetachably united with said steel, said stone having a working faceforming a smooth continuation of the working face of said steel.

10. In a knife sharpener, an elongated sharpening element comprising asection of knife steel, said section being reduced incrosssectionfor aportion of its length to provide a supporting face set back from theworking face of said steel, an elongatedsectionof abrasive stonesupported on said supportingja ce and having a working face formingacontinuation of the working face of said steel, and spring clipsremovably holding said abrasive stone in place.

YERME H. SHAIN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 602,192 Maillot Apr. 12, 18981,059,491 Schwartz Apr. 22, 1913 1,068,973 Brown July 29, 1913 1,463,653Loomis July 31, 1923 1,907,870 Reader May 9, 1933 2,432,231 Elphee Dec.9, 1947 2,443,821 Gray June 22, 1948

